public GridModel(IQueryable <T> rows, GridStateModel gridState, FilterModel filterModel, string gridID, string refreshJavascriptFunctionName) : base(gridID, refreshJavascriptFunctionName)
{
this.FilterModel = filterModel;
rows = this.ExecuteFiltersOnRows(rows);
rows = this.ExecuteSorting(rows, gridState);
this.PaginationModel = new GridPaginationModel(rows.Count(), gridState.SelectedPage, gridState.ItemsPerPage, gridID, refreshJavascriptFunctionName);
this.Rows = this.ExecutePagination(rows);
}
private IQueryable <T> ExecuteSorting(IQueryable <T> rows, GridStateModel gridState)
{
if (gridState.FilterState == null)
{
return(rows);
}
SortingDirection sortingDirection = gridState.FilterState.SortingDirection;
string sortingColumn = gridState.FilterState.SortingColumn;
Type sortingColumnType = gridState.FilterState.SortingPropertyType;
if (string.IsNullOrWhiteSpace(sortingColumn) || sortingDirection == SortingDirection.Undefined)
{
return(rows);
}
// If the source type is Interface, which inherits another Interface, and the property belongs to this base Interface,
// 'Expression' will throw an error. Then, sorting needs to be done by this base Interface type.
Type sortingType = this.GetExpressionType(sortingColumn);
// If the source type is Interface, and if the property, by which sorting is executing, is not declared on the source type,
// but on the Interfaces that this source Interface inherits, than the sorting must be done in the Interface which declares
// the property by which sorting is executing
object sortingRows = this.CastSourceRowsToTheProperExpressionType(sortingType, rows);
ParameterExpression sortingParameter = Expression.Parameter(sortingType, "p");
Expression parameterExpression = Expression.PropertyOrField(sortingParameter, sortingColumn);
LambdaExpression sortingExpression = Expression.Lambda(parameterExpression, new[] { sortingParameter });
string sortingMethodName = string.Empty;
switch (sortingDirection)
{
case SortingDirection.Ascending:
sortingMethodName = "OrderBy";
break;
case SortingDirection.Descending:
sortingMethodName = "OrderByDescending";
break;
}
MethodInfo sortingMethod = typeof(Queryable).GetMethods().Where(m => m.Name.Equals(sortingMethodName)).Where(m => m.GetParameters().Length == 2).Single();
MethodInfo genericSortingMethod = sortingMethod.MakeGenericMethod(new[] { sortingType, parameterExpression.Type });
object sortedRows = genericSortingMethod.Invoke(null, new object[] { rows, sortingExpression });
return(this.CastRowsToTheSourceType(sortingType, sortedRows));
}
